The invention relates firstly to a wheel-hub assembly for a vehicle wheel, with a wheel hub which is arranged so as to be capable of rotating on a torsion-resistant steering knuckle via a hub bearing assembly and which terminates inside the vehicle in a hub neck, the inner periphery of which defines an opening for the central passage of the steering knuckle, and on which an attachment portion of a pole ring of an ABS sensor is mounted, wherein a component of the pole ring is a pulse-generator portion integrally formed with the attachment portion, which extends, starting from the attachment portion, toward the wheel-hub axis. The invention further relates to a wheel-hub assembly as described, which is provided with openings, preferentially slots, uniformly distributed in the peripheral direction.
The invention relates further to a pole ring for an ABS sensor for sensing the rotation of a vehicle wheel, with an attachment portion for mounting the pole ring on a hub of the vehicle wheel, and with a pulse-generator portion integrally formed with the attachment portion, which extends, starting from the attachment portion, as a ring, closed in the peripheral direction, toward the pole-ring axis and is provided with openings, preferentially slots, uniformly distributed in the peripheral direction. Such a pole ring is particularly suitable for use in a wheel-hub assembly according to the invention.
A wheel-hub assembly with pole ring of the afore mentioned kind is known from DE 10 2011 000 626 A1. The wheel hub is arranged so as to be capable of rotating on a torsion-resistant steering knuckle via a hub bearing assembly, and terminates inside the vehicle in a hub neck, the inner periphery of which defines an opening for the central passage of the steering knuckle on which the wheel hub is supported in a bearing so as to be capable of rotating. The outer periphery of the hub neck is designed to attach the pole ring of an ABS sensor. For this purpose the pole ring is provided with an attachment portion which is supported from the outside on the outer periphery of the hub neck. A component of the pole ring is, furthermore, a pulse-generator portion which is integral with the attachment portion of the pole ring and which, starting from the attachment portion, extends toward the central axis of the wheel hub. On the pulse-generator portion the pole ring is provided with slots uniformly distributed in the peripheral direction. The ABS sensor is attached in the region of the steering knuckle in such a way that it is situated exactly opposite the slots and in this way senses the speed of rotation of the pole ring and converts said speed into a corresponding control signal of an anti-lock braking system or, in the case of a driven vehicle axle, into a control signal of a drive control system.
A similarly constructed assembly consisting of a wheel hub and a pole ring attached thereto is known from DE 103 49 303 B3, for example.
A feature that is common to the wheel-hub assemblies of the prior art is that, viewed from the interior of the hub, the pole ring arranged on the vehicle-interior opening of the wheel hub constitutes a step or edge on which, if the peripheral portion in question is located underneath, dirty water or even fine particles of dirt can settle and accumulate. As a consequence, and depending on the materials being used, the formation of rust may occur there in the course of time. This effect is intensified the more dirt gets behind the pole ring from inside the vehicle and such dirt then accumulates between the pole ring and the bearing seal arranged behind it in the interior of the hub. This dirt—above all, coarse dirt—may also result in the described corrosion problems in the course of time. The consequences may be an inseparable sticking of the pole ring to the hub, or an inadequate true running of the pole ring, which once again has consequences for the accuracy of the ABS sensor signal.
The object underlying the invention is therefore to create solutions for the contamination problems and associated corrosion problems in the region between the pole ring and the interior of the hub arranged behind it.